French dark fantasy comic/graphic novel, babies are always born as twins and fight during birth

I read an English scanlation of this on a manga site back in the teens. The premise was that babies are always born as twins, and fight viciously during birth. This always results in the loser being disfigured to some degree. The non-disfigured child becomes a full member of society, while the disfigured ones are an underclass who do all the dirty work and are conscripted into this society's endless wars. The story follows one set of twins who may be children of prophecy as they were both born without disfigurement (but one became disfigured immediately after birth).